From the past, an image display apparatus such as a projector is widely used. For example, light from a light source is modulated by a light modulator such as a liquid-crystal device and the modulated light is projected onto a screen or the like. In this manner, an image is displayed. In the recent years, a projector using a laser light source as the light source also has been developed. Patent Document 1 describes a technology relating to an illumination optical system of such a projector.
Patent Document 1: Japanese Patent Application Laid-open No. 2013-15762